New Study Will Examine Hydrate Blockage in Subsea Jumpers

Posted by Michelle HowardOctober 12, 2017

The University of Western Australia (UWA) is leading a joint industry project (JIP), supported by the Industry Technology Facilitator (ITF), to provide industry with a better understanding of the mechanism of hydrate growth and blockages.

The 12-month study, entitled ‘Hydrate Deposit Growth in Subsea Jumpers (HyJump)’, currently has the support of industry partners, including Chevron(CVX), Total and Woodside, and is welcoming more participants to join the project.

To simulate the flow geometry and risk of hydrate blockage in subsea equipment, the project will see the development of a new 2” jumper test section on the Hytra flowloop, owned by CSIRO and jointly operated by CSIRO and UWA, in Western Australia. This will be used to characterise the growth rate and severity of hydrate blockage formation in this subsea geometry, which will provide unique insight into management methods for transient, multiphase conditions.

The results of the study may be used to determine how a temporary or permanent reduction in hydrate management chemicals, such as Thermodynamic Hydrate Inhibitors (THI), affects the risk of blockage over a variety of restart conditions. Results will also allow assessing how Low Dosage Hydrate Inhibitors (LDHIs) can prevent such blockages.

Will Davies, General Manager with ITF, said: “While previous studies have evaluated hydrate blockage risk for inclined pipe segments, the HyJump Project seeks to enhance that knowledge further. It will investigate the viability of allowing gas to sweep liquids from the affected section, further analysis of chemical injection to clear blockages and aims to deliver novel insight and experimental data that may be used to enhance existing multiphase flow/analysis tools, or service as a guideline to support risk-based system designs or operating conditions.”

Currently, there are limited laboratory-based studies using a prototype system to investigate hydrate risk management in jumpers. The HyJump JIP aims to perform functional and performance testing to advance this approach to create a full-scale prototype for eventual environment testing.

Fourteen tests will be performed with the simulated jumper and the results will provide new experimental evidence to determine the criteria and allowable conditions to restart subsea gas pipelines hydrate-inhibition strategies may be viable for high-risk geometries in the future.

Dr Zachary Aman, Associate Professor of Chemical Engineering at The University of Western Australia added: “This project builds upon a strong track record on the unique, single-pass gas flowloop in Perth. Our new understanding of hydrate blockage formation in horizontal pipelines has led us to extend the flowloop capability with CSIRO toward the subsea systems that are exposed to harsh multiphase flow conditions. We are grateful to have outstanding partners, and are excited to deploy this unique piece of equipment to better manage the risk of hydrate blockage in subsea systems.”